How to rinse off UV die on a leaking car a/c system?

Any of the usual solvents, I'd guess. White spirit might be the easiest.

they make actual dye solvent, any ac place will have it, called dye-b-gone or something similar.

They've all got "amusing" names like dye-away, dye-free or glo-cleaner

Nedavno Mrcheerful napisa:

I was thinking of some DIY solution (where I am it is not easy to find what you are talking about), something like suggested white spirit.

BTW i tried to rinse condenser with petrol, and it worked. I got it (almost) completely off, and I am going to test it now for leaks.

I would think a pressure washer or steam cleaner will do the job ok, but make sure there is pressure in the system first or you will damage the whole system with the water.

the usual way to test will be to pressurise with Nitrogen. or use a gas sniffer if there is any refrigerant pressure left.

Nedavno Mrcheerful napisa:

You mean that I have pressure in the a/c system so that water does not get inside trough leak point? If so I still have pressure, as it still blows cold air, but not cold enough. And I can see liquid refrigerant with bubbles at the sight-glass.

I do not have access to a gas sniffer, but UV die is inside, so UV-lamp and goggles should be OK.

yes, moisture in the system is a major no-no, for several reasons.

bubbles visible is not abnormal.

Once you have replaced the leaking bits plus the dryer the correct procedure is to vacuum down and make sure vacuum can be held, then fill with the correct amount of fresh gas plus oil/dye/leakstop as needed. then test, get the running pressures and ambient and delivered temperatures and check them against the ideals from the makers.

Mrcheerful

Nedavno Mrcheerful napisa:

Yes, I know all that, thank you.

Any tips on how to change oil in complete system? Or, since I am probably going to change condenser and evaporator, how to drain oil from the compressor?

I am asking this since a/c shop filled the system with R-134, not with R-12 as they should. They claim that oil is compatible with both R-12 and R134, but I do not trust them any more. So now I have new dryer, a bottle of R-12 and a can of mineral a/c oil.

Is there a drain plug ore something on the compressor? Or do I need to get it off?

Original oil is not compatible, there are replacement types that are.

There are special flushing kits available to get all the old junk out.

You need to remove the compressor, turn it upside down, let the oil all fall out, rotating the compressor as needed.

Nedavno Mrcheerful napisa:

OK, thank you.

Then vacuum the sytem down before putting anything back in. (tool hire shops rent vacuum pumps for diamond drilling rigs if you've not got anyone helpfull nearby)

I have another question.

Before R-12 escaped, while a/c system was fully charged, it would not blow colder than ~14 deg Celsius (Fan set on high, car in the garage - not in the sun, ambient temperature ~30C). High pressure pipe warm, low side cold and wet. Compressor does not cycle on and off, it's on constantly. Very little, almost no water under the car from condensation. After few days it was colder ~17C and I could hear a click under the dash, and revs and load would go down, so I guess that icing prevention is OK.

I was told at another ng that this might happen if evaporator is dirty (I do not have a/c filter in this car). I do not see logic there. If it was dirty, less air would go around it, it would ice-up, and compressor should stop. And if icing happens when I set fan to high (or switch a/c off) it should melt, and there should be some water underneath the car.

Any thoughts on this?

not if it's coated in dirt rather than clogged with dirt. However it sounds more likely that you're low on coolant

Nedavno Duncan Wood napisa:

No, I have enough R-12 in the system, I have a bottle of R-12, and I added ~1kg as it says in the manual (no bubbles in sight-glass).

And what happens if evaporator is coated in dirt?

Then the dirt insulates it from the air.

Was the system vacuumed correctly before adding the refrigerant? If you have just fitted all this lot then I would assume you know the condition of the parts and that they were clean.

Nedavno Duncan Wood napisa:

So it blows warm... And why is the compressor always on? Why ice preventing sensor does not kick in and power off the compressor? And there should be some water sipping out the drain hoses.

Because the airs hot.

Because it's not iced up.

Only if the airs being chilled enough.

Nedavno Mrcheerful napisa:

I think that it wasn't. Another reason for me trying to do the work...

It looked clean, but for the start I connected all together just to see if it will work. It came in few bits: one under the dash with heater , evaporator, flaps... then the compressor, condenser and hoses. I bought new dryer.

I guess that if I want to get it working as it should, I'll have to get that manifold with gauges next...